Just ask her out.
When is it good to ask her out? Do you have to find her randomly and talk to her till she feels confortable with you?
Sometimes I think it's too ovbious. I think these sentences are the same:
Let's go out= You wanna be my girl????
I feel like if the girl says no, I won't be able to keep working on her and make her go out with me...
What I want to know is when it's good to ask girls out.